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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,122 Views)
Wolf Eagle
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Tyrannosaurus rex
Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex (rex meaning "king" in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 67 to 65.5 million years ago.[1] It was among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators. By far the largest carnivore in its environment, Tyrannosaurus rex may have been an apex predator, preying upon hadrosaurs and ceratopsians, although some experts have suggested it was primarily a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running in paleontology. Tyrannosaurus rex was one of the largest land carnivores of all time; the largest complete specimen, FMNH PR2081 ("Sue"), measured 12.8 metres (42 ft) long, and was 4.0 metres (13.1 ft) tall at the hips. Mass estimates have varied widely over the years, from more than 7.2 metric tons (7.9 short tons), to less than 4.5 metric tons (5.0 short tons), with most modern estimates ranging between 5.4 and 6.8 metric tons (6.0 and 7.5 short tons). Packard et al. (2009) tested dinosaur mass estimation procedures on elephants and concluded that dinosaur estimations are flawed and produce over-estimations; thus, the weight of Tyrannosaurus could be much less than usually estimated. Other estimations have concluded that the largest known Tyrannosaurus specimens had a weight exceeding 9 tonnes.

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Spinosaurus aegyptiacus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. Spinosaurus may be the largest of all known carnivorous dinosaurs, even larger than Tyrannosaurus and Giganotosaurus. Estimates published in 2005 and 2007 suggest that it was 12.6 to 18 metres (41 to 59 ft) in length and 7 to 20.9 tonnes (7.7 to 23.0 short tons) in weight. The skull of Spinosaurus was long and narrow like that of a modern crocodilian. Spinosaurus is thought to have eaten fish; evidence suggests that it lived both on land and in water like a modern crocodilian. The distinctive spines of Spinosaurus, which were long extensions of the vertebrae, grew to at least 1.65 meters (5.4 ft) long and were likely to have had skin connecting them, forming a sail-like structure, although some authors have suggested that the spines were covered in fat and formed a hump. Multiple functions have been put forward for this structure, including thermoregulation and display. Dal Sasso et al. (2005) assumed that Spinosaurus and Suchomimus had the same body proportions in relation to their skull lengths, and thereby calculated that Spinosaurus was 16 to 18 meters (52 to 59 ft) in length and 7 to 9 tonnes (7.7 to 9.9 short tons) in weight. The Dal Sasso et al. estimates were criticized because the skull length estimate was uncertain, and (assuming that body mass increases as the cube of body length) scaling Suchomimus which was 11 meters (36 ft) long and 3.8 tonnes (4.2 short tons) in mass to the range of estimated lengths of Spinosaurus would produce an estimated body mass of 11.7 to 16.7 tonnes (12.9 to 18.4 short tons).

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Edited by Taipan, Apr 24 2015, 10:10 PM.
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Ceratodromeus
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Utahraptor
Nov 18 2014, 03:00 AM
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Where is it gonna strike with those huge arms and claws? the shins? meanwhile its head is getting chomped. Just by looking at this comparison we can conclude the arms wouldn't have been a difference maker against a big theropod. They were robust because they needed to support its body weight on land and grasp/slash marine life in the water.

Now if it were to be attacked by something like a crocodile then they would be effective defensive weapons because it would be lower to the ground.
the tyrannosaurus in that comparison is too tall.
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Jiggly Mimus
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Umm wasn't there a study about how Spinosaurus bite was extremely powerful coming only slightly less then t-rex. Wouldn't T-rex need to lean in on it and if it does it can just bite and tear at the neck or standup and knock T-rex down and fataly bite or stab into the T-Rex.
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Tyrant
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I was talking about the modern analogues you claimed to fail frequently when grappling prey. While I think the functional morphology in this case speaks for itself, it should bee pointed out that these also frequently succeed, and that with prey significantly larger thaan themselves. Of course many predators fail more often than they succeed, but that is not restricted to grapplers


Oh. Well in that case something you need to note is that there is a lot more to grappling than just strength. From what I derived from the many feline vs canine debates oart of the reason or in fact the primary reason the former are capable of occasionally restraining large prey like buffalo is because of flexibility, which makes sense since it would be awfully strange that a five hundred pound lion could actually overpower an animal four times its size. Spinosaurus and tyrannosaurus on the other hand are both theropods with the former being better suited for aquatic life so it is highly unlikely it would have the same advantages a lion would have over something like a buffalo or zebra.

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Umm wasn't there a study about how Spinosaurus bite was extremely powerful coming only slightly less then t-rex.


No such study exists. Just by looking at their skulls it is clear that tyrannosaurus has a massive edge in the bite department.

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Wouldn't T-rex need to lean in on it and if it does it can just bite and tear at the neck or standup and knock T-rex down and fataly bite or stab into the T-Rex.


If height were such a detrimental attribute in a fight tyrannosaurs would have probably evolved to become shorter and stockier as a result. This is clearly not the case so its unlikely such a scenario would happen more often than not.
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genao87
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Is it already accepted and proven that Spino was this low to the ground? I understand that Cau wants Spino to be much lower than others have calculated....is his study method has been accepted officially that Spino was this low to the ground and weigh in like 7 tons?
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Fist of the North Shrimp
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The study is not by Cau, he just knew about it way before it was published(Just as he knows about other stuff in advance). And yes, the legs were that short.
Though Cau already proposed a different posture.
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theropod
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@jiggly: Nope, there was no such study.

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Oh. Well in that case something you need to note is that there is a lot more to grappling than just strength.
No, but strenght is a major factor, arguably the most important for any sort of grappling together with the ability to grasp, clutch or otherwise anchor its arms to something (which Spinosaurus had due to its large claws and medially facing manus with opposing palms).

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From what I derived from the many feline vs canine debates oart of the reason or in fact the primary reason the former are capable of occasionally restraining large prey like buffalo is because of flexibility, which makes sense since it would be awfully strange that a five hundred pound lion could actually overpower an animal four times its size.
We’re not talking about Spinosaurus overpowering something four times its size. The people who have been discussing this are referring to similar sized animals.

That’s beside the point though. The relevant point here is the ability of the forelimbs to assume a grappling position, which those of Spinosaurus have (in fact all known non-avian theropod forelimbs are permanently fixed in this posture), and the availability of sufficient strenght and grappling tools where they are needed. That’s why feline forelimbs, which can be rotated so that the palms face medially and that have sharp claws and the necessary antebrachial musculature, are well-suited for grappling, while canid forelimbs, which concentrate the musculature on the humerus and shoulder, have the palms permanently facing down/backwards and only bear blunt, non-raptorial claws aren’t.

You cannot say that a wolf’s limbs per se is weaker than that of a similar-sized cat, but it lacks the types of musculature that are necessary in performing movements aside from running–and hence there are no reasons to even be able to perform these at all (hence they are less flexible). That”s a more efficient arrangement for running because it doesn’t require unneeded musculature just to stabilize the limb.
Megalosaurs and Carnosaurs are actually adapted for clutching in a similar way. Their range of movement is also restricted, in a way that allows the types of movement necessary for grappling but not those for locomotion. Hence why the palms are facing medially and there is no pronation ability, and why there’s no excessive ark of anterior motion that apparently isn’t necessary for their purpose.

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Spinosaurus and tyrannosaurus on the other hand are both theropods with the former being better suited for aquatic life so it is highly unlikely it would have the same advantages a lion would have over something like a buffalo or zebra.
What does being aquatic have to do with it?

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If height were such a detrimental attribute in a fight tyrannosaurs would have probably evolved to become shorter and stockier as a result.
Tyrannosaurids were relatively tall because this attribute is invariably connected to their cursoriality. Cursoriality can be detrimental, not so much because of the height but because it commonly comes at the expense of limb robusticity and especially flexibility.
Height itself is a double edged sword, it’s detrimental to balance, but that can be made up for, and helps with strenght and reach, allowing to attack from above, which can also be nullified if the opponent has superior balance in exchange.
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genao87
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MantisShrimp
Nov 18 2014, 07:14 AM
The study is not by Cau, he just knew about it way before it was published(Just as he knows about other stuff in advance). And yes, the legs were that short.
Though Cau already proposed a different posture.
What posture is this?..cause right now, Spino legs were shorter but never this low proposed by this model!

Scott Hartman and a couple of others are rejecting the height...
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Fist of the North Shrimp
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That was before Ibrahim posted a response to the criticism. It all startend when people relied on Photoshop and not the actual fossils. The verts Werke meadured rim to rim(funtional lenght) and the femur is pretty bent. The whole issue would not even have ariden if the authors would haven been contacted beforehand.
The posture proposed by Cau is a more upright Position(No knuckle-walking) and a more erect neck.
I have to completely agree with him on the latter, the spines would be perfect attachement points for the ligaments.
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Sleipnir
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Strange how long a thread like this will last, and gradually go off the topic, anyway I favor the more famous one because the less famous has perhaps a weaker bite and jurassic park 3 was biased.
Edited by Sleipnir, Nov 18 2014, 11:40 AM.
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Jiggly Mimus
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If I have study right... didn't T-Rex have a really bad balance and it could have been fairly easy to tip it over? Therefore Spino has power and could rear up and knock him to the ground and do whatever Spino has to do.
Or am I completely misunderstanding.
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Sarcoimperator
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Jiggly Aegypticus
Nov 19 2014, 12:51 AM
If I have study right... didn't T-Rex have a really bad balance and it could have been fairly easy to tip it over? Therefore Spino has power and could rear up and knock him to the ground and do whatever Spino has to do.
Or am I completely misunderstanding.
An 8 tonne tyrannosaurus on thick sturdy legs certainly didn't have bad balance. Face to face none of them would be able to tip over the other one.
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Ceratodromeus
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Sarcoimperator
Nov 19 2014, 01:26 AM
Jiggly Aegypticus
Nov 19 2014, 12:51 AM
If I have study right... didn't T-Rex have a really bad balance and it could have been fairly easy to tip it over? Therefore Spino has power and could rear up and knock him to the ground and do whatever Spino has to do.
Or am I completely misunderstanding.
An 8 tonne tyrannosaurus on thick sturdy legs certainly didn't have bad balance. Face to face none of them would be able to tip over the other one.
adding to this, the long stiffened tail of theropods served as a counterbalance.
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Ausar
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Apparently one member on another forum contacted Simone Maganuco (one of the people who worked on "Semiaquatic adaptations in a giant predatory dinosaur") who gave what he thinks of S. aegyptiacus's body mass.

"I can say that the body mass estimate for the reconstructed adult Spinosaurus is between 6 and 7 tons. It was written and discussed in the first version of the manuscript, but not included in the very trimmed final version. It will be included in the next more detailed papers.


The old reconstruction was less accurate. We did not know the new skeleton and its proportions at that time (2005), so we were forced to include in our reconstruction many elements from Suchomimus and Baryonyx just to have an idea of the size of Spinosaurus. In the 2005 reconstruction the body was slightly bigger respect to the head, and the legs - above all the thighs - were way bigger than now. I hope we will have more material for the next reconstruction, but I think that the size and proportions will not change too much. The important thing is that the adults of Spinosaurus attained a considerable size, but they were not heavier than tyrannosaurs and large charcarodontosaurids (based on my observations on the specimens I would say that the largest specimens of Tyrannosaurus was heavier than our reconstruction of the adult Spinosaurus)."


According to the aforementioned other-forum member, Maganuco meant metric tons (tonnes) when he said tons.
Edited by Ausar, Nov 19 2014, 05:42 AM.
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TheROC
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genao87
Nov 18 2014, 08:29 AM
MantisShrimp
Nov 18 2014, 07:14 AM
The study is not by Cau, he just knew about it way before it was published(Just as he knows about other stuff in advance). And yes, the legs were that short.
Though Cau already proposed a different posture.
What posture is this?..cause right now, Spino legs were shorter but never this low proposed by this model!

Scott Hartman and a couple of others are rejecting the height...
There is supposedly more Spinosaurus info to come from other groups, including a study that is going to seperate Spinosaurus into two distinct species.

Seth Sorensen of Fossilshack remarked on that coming down the pipeline from people he knows, and he also completely disagreed with their proportions, saying he had Spinosaurus leg bones, that if scaling by the studies proportions, would make the animal that his came from twice as big as their proposed model. He said they will be donating their material to some universities soon.

There's more to come.

Edited by TheROC, Nov 19 2014, 10:05 AM.
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Ceratodromeus
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Ausar
Nov 19 2014, 05:40 AM
Apparently one member on another forum contacted Simone Maganuco (one of the people who worked on "Semiaquatic adaptations in a giant predatory dinosaur") who gave what he thinks of S. aegyptiacus's body mass.

"I can say that the body mass estimate for the reconstructed adult Spinosaurus is between 6 and 7 tons. It was written and discussed in the first version of the manuscript, but not included in the very trimmed final version. It will be included in the next more detailed papers.


The old reconstruction was less accurate. We did not know the new skeleton and its proportions at that time (2005), so we were forced to include in our reconstruction many elements from Suchomimus and Baryonyx just to have an idea of the size of Spinosaurus. In the 2005 reconstruction the body was slightly bigger respect to the head, and the legs - above all the thighs - were way bigger than now. I hope we will have more material for the next reconstruction, but I think that the size and proportions will not change too much. The important thing is that the adults of Spinosaurus attained a considerable size, but they were not heavier than tyrannosaurs and large charcarodontosaurids (based on my observations on the specimens I would say that the largest specimens of Tyrannosaurus was heavier than our reconstruction of the adult Spinosaurus)."


According to the aforementioned other-forum member, Maganuco meant metric tons (tonnes) when he said tons.
i too saw/ debated what that member had said, however the lack of reasoning for a downsization, and the equally ambiguous reply i got from maganuco, casts doubt for me. proportions of the 3D model this bases off of are...off... to me. it's been reported the proportions obtained from the study yield a animal ~2x larger then the figure this new paper suggests.

Edit: TheRoc already addressed the my last point there
Edited by Ceratodromeus, Nov 19 2014, 11:50 AM.
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